In the hydrogen atomic spectrum,a series limit is found at $12186.3 \ cm^{-1}$. To which series does it belong?

In an orbital,the value of $K.E.$ is equal to:

The ratio of kinetic energies of photoelectrons emitted from a metal by light of frequencies $v_1$ and $v_2$ is $1 : 2$. The threshold frequency of the metal will be:

The ionization energy of a hydrogen atom is $13.6 \ eV$. The energy required to excite the electron in a hydrogen atom from the ground state $(n=1)$ to the first excited state $(n=2)$ is (Note: The question asks for energy per atom in Joules. Given $1 \ eV = 1.602 \times 10^{-19} \ J$)

In which one of the following pairs of experimental observations and phenomena does the experimental observation correctly account for the phenomenon?

The graph that depicts Einstein's photoelectric effect for a monochromatic source of frequency above the threshold frequency is